منابع مشابه
Water vapour in circumstellar envelopes
We present observations of the 313 →220 line of p-H2O at 183 GHz in the direction of the circumstellar envelopes of 23 O–rich evolved stars. The 183 GHz data are complemented with observations of CO J=2 →1, p-H2O 515 →422 at 325 GHz, o-H2O 616 →523 at 22 GHz and SiO v=1 J=2 →1. The line profiles of these transitions are compared and discussed in terms of the regions where they are formed. We ha...
متن کاملInfrared interferometry of circumstellar envelopes
This paper will review the technical progress of interferometric infrared observing techniques from the first 2-element interferometer 25 years ago to the 3+ element arrays now coming into service. To date, only the Infrared Spatial Interferometer (ISI) has published separateelement interferometric data on circumstellar dust shells in the infrared and many of these scientific results will be di...
متن کاملA survey of CN in circumstellar envelopes
We have conducted a survey of CN N=2–1 and N=1–0 line emission in the envelopes of evolved stars. The sample consists of 42 objects, including C-rich and O-rich envelopes, S-stars, detached envelopes, and proto-planetary nebulae. Confident detections have been achieved in 30 objects. Both CN lines are bright in C-rich envelopes, and the 2–1 line has been detected in 5 O-rich objects (previously...
متن کاملSmall Carbon Chains in Circumstellar Envelopes
Observations of carbon-rich circumstellar envelopes were made using the Phoenix spectrograph on the Gemini South telescope to determine the abundance of small carbon chain molecules. Vibration–rotation lines of the ν3 antisymmetric stretch of C3 near 2040 cm−1 (4.902 μm) have been used to determine the column density for four carbon-rich circumstellar envelopes: CRL 865, CRL 1922, CRL 2023 and ...
متن کاملChemistry in oxygen-rich circumstellar envelopes
We have considered the chemistry occuring in the circumstellar envelope surrounding an oxygen-rich AGB star and have specifically modelled 4 sources; R Dor, TX Cam, OH231.8+4.2 and IK Tau. Methane has been assumed to be a parent molecule and the resulting carbon chemistry is investigated. We find that carbon chain molecules up to C2H4 can be abundant as can CH3CN and CH3OH. Our model extends pr...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2001
ISSN: 0035-8711,1365-2966
DOI: 10.1046/j.1365-8711.2001.04429.x